Wanted: GC8 Waste Gate Actuator Arm

[JDB]

Ok, looking to find someone with a dead turbo kicking around that is willing to sell me a waste gate off of it. I believe all I need is the arm but don't know for sure if they come off on a GC8 yet. Don't care if its off a TD04 or TD05. Want to try an experiment with it fix boost spike on these cars. If it works, it will benefit us all! There's enough people on here with these cars that I figured I'd try...

[Speed Stick]

Oh no way! I threw my entire actuator away when I moved from Victoria to Halifax last month.... Sorry man. Shouldn't be too tough to find one though.

[JDB]

Originally Posted by Speed Stick

Oh no way! I threw my entire actuator away when I moved from Victoria to Halifax last month.... Sorry man. Shouldn't be too tough to find one though.

Damn! Yeah, I sold a spare turbo before I thought of this too.... oh well

[GC8REX]

This would be for boost creep, not boost spike wouldn't it?

Good luck finding one man, I encounter creep in my higher gears when boosting and I'm sure there are tons of us that would appreciate a fix.

I'm guessing you want to move the arm further up on the wastegate in order to let it open more?

[JDB]

Originally Posted by GC8REX

This would be for boost creep, not boost spike wouldn't it?

Good luck finding one man, I encounter creep in my higher gears when boosting and I'm sure there are tons of us that would appreciate a fix.

I'm guessing you want to move the arm further up on the wastegate in order to let it open more?

No, boost creep has to do with the size of the waste gate and not being able to keep up with the high exhaust flows. Boost spike has to do with the ability to dump pressure fast enough. So yes I want to shorten the rod and re-wire my EMBC to shut off in the high boost setting. If theory translate into reality I should be able to hit 18psi with zero boost spike and minimal fade. I'm not impressed with the amount of fluctuation of pressure on these cars after 2 different controllers and this is a cheaper mod than going to an external waste gate with replaceable springs. But will see if I can get parts.....

Do you have a EMBC? I never have creep issues, but I can vent pressure with mine.

[GC8REX]

Originally Posted by JDB

No, boost creep has to do with the size of the waste gate and not being able to keep up with the high exhaust flows. Boost spike has to do with the ability to dump pressure fast enough. So yes I want to shorten the rod and re-wire my EMBC to shut off in the high boost setting. If theory translate into reality I should be able to hit 18psi with zero boost spike and minimal fade. I'm not impressed with the amount of fluctuation of pressure on these cars after 2 different controllers and this is a cheaper mod than going to an external waste gate with replaceable springs. But will see if I can get parts.....

Do you have a EMBC? I never have creep issues, but I can vent pressure with mine.

The main reason people mod their wastegates is for creep, which I notice is a lot worse than spike on our cars, but maybe its just my catless exhaust setup. Less backpressure downstream=higher flows which the wastegate can't match.

Hallman MBC, with that antispiking vent. Don't find spike is much of a problem, I set it so that nearing redline in a gear its hitting my target boost, when I first floor it maybe it starts at 16.5 and gets to 18 by the end of the gear, don't find this a real issue though.

[JDB]

Here's a picture of what i'm after. Just pulled mine and took a look, it is all one piece. So I guess I need a whole waste gate.
IMG_0449

Originally Posted by GC8REX

The main reason people mod their wastegates is for creep, which I notice is a lot worse than spike on our cars, but maybe its just my catless exhaust setup. Less backpressure downstream=higher flows which the wastegate can't match.

Hallman MBC, with that antispiking vent. Don't find spike is much of a problem, I set it so that nearing redline in a gear its hitting my target boost, when I first floor it maybe it starts at 16.5 and gets to 18 by the end of the gear, don't find this a real issue though.

Well, I've read a lot and see there is quite a few people on NASIOC chatting about this mod on newer wrx's. Seemed to be skirting the whole issue on how it works or their back and forth on it.
Boost creep happens when your waste gate is fully open and the exhaust can't get out the turbo outlet fast enough, so the turbo keeps spooling after the fact. The only fix is a bigger after market waste gate. When the waste gate opens is what the spring controls but can be adjusted by adding a controlled amount of pressure through a BC. If you unhook the BC or it fails you get a waste gate release at the pressure you spring compresses. In the case of a GC8, 7-8psi. By shortening the rod you change how much force it takes to overcome the spring rate. Which in turn pushes the psi pressure up.

I have full headers and full exhaust but have never had boost creep so thats strange... But I can get spike to 22psi with boost set at 16psi and venting at 60%. So guess I need to keep working out the kinks... You must have a large vent on yours. Adding another vent is an idea I have too.

[GC8REX]

Originally Posted by JDB

Well, I've read a lot and see there is quite a few people on NASIOC chatting about this mod on newer wrx's. Seemed to be skirting the whole issue on how it works or their back and forth on it.
Boost creep happens when your waste gate is fully open and the exhaust can't get out the turbo outlet fast enough, so the turbo keeps spooling after the fact. The only fix is a bigger after market waste gate. When the waste gate opens is what the spring controls but can be adjusted by adding a controlled amount of pressure through a BC. If you unhook the BC or it fails you get a waste gate release at the pressure you spring compresses. In the case of a GC8, 7-8psi. By shortening the rod you change how much force it takes to overcome the spring rate. Which in turn pushes the psi pressure up.

I have full headers and full exhaust but have never had boost creep so thats strange... But I can get spike to 22psi with boost set at 16psi and venting at 60%. So guess I need to keep working out the kinks... You must have a large vent on yours. Adding another vent is an idea I have too.

Hmm have you looked up your specific BC in case others have had that problem? That's brutal spiking .

My thought to reduce creep was to attach the actuator rod to a higher or lower location on the valve itself in order to allow more air to flow by in case it is not opening fully in stock form (designed for lots of backpressure). It would essentially move the pivot point of the valve to a spot where the same amount of pressure opens it more fully, allowing more air through. Just ideas though, my creep isn't serious enough to warrant major work like that just yet.

In other news, my wastegate has rust along the top almost exactly like that one in the picture

[JDB]

Thinking in going to build a hybrid boost controller as well. They sound complicated to setup but everything I find seems to say they are the way to go for total control. Rob told me his fueling maps should take it too. So no tuning head-aches like the 02+ guys.

Still want a waste gate so...bump!